web-animations/timing-model/animations/canceling-an-animation.html

<!DOCTYPE html>
<meta charset=utf-8>
<title>Canceling an animation</title>
<link rel="help"
    href="https://w3c.github.io/web-animations/#canceling-an-animation-section">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../testcommon.js"></script>
<body>
<div id="log"></div>
<script>
"use strict";

promise_test(t => {
  const animation = createDiv(t).animate(null, 100 * MS_PER_SEC);
  const retPromise = animation.ready.then(() => {
    assert_unreached('ready promise was fulfilled');
  }).catch(err => {
    assert_equals(err.name, 'AbortError',
                  'ready promise is rejected with AbortError');
  });

  animation.cancel();

  return retPromise;
}, 'A play-pending ready promise should be rejected when the animation is'
   + ' canceled');

promise_test(t => {
  const animation = createDiv(t).animate(null, 100 * MS_PER_SEC);
  return animation.ready.then(() => {
    animation.pause();
    // Set up listeners on pause-pending ready promise
    const retPromise = animation.ready.then(() => {
      assert_unreached('ready promise was fulfilled');
    }).catch(err => {
      assert_equals(err.name, 'AbortError',
                    'ready promise is rejected with AbortError');
    });
    animation.cancel();
    return retPromise;
  });
}, 'A pause-pending ready promise should be rejected when the animation is'
   + ' canceled');

promise_test(t => {
  const animation = createDiv(t).animate(null);
  animation.cancel();
  return animation.ready.then(p => {
    assert_equals(p, animation);
  });
}, 'When an animation is canceled, it should create a resolved Promise');

test(t => {
  const animation = createDiv(t).animate(null);
  const promise = animation.ready;
  animation.cancel();
  assert_not_equals(animation.ready, promise);
}, 'The ready promise should be replaced when the animation is canceled');

</script>
</body>